In the crystalline lattice structure of Si, the valence electrons of every Si atom are locked up in covalent bonds with the valence electrons of four neighboring Si. Michael Tooley BA. Formerly Vice Principal. Brooklands College of Further and Higher Education. Electronic Circuits: Fundamentals and. Applications. Electronics has undergone important and rapid developments over the last 60 years, which have generated a large range of theoretical and.
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PDF Drive is your search engine for PDF files. As of today we have 78,, eBooks for you to download for free. No annoying ads, no download limits, enjoy . and electronic circuits and soldering irons. Atoms are not solid but composed of three fundamental particles: electrons, protons, and neutrons arranged in. 5. Fundamentals of Electronic Circuit Design. Outline. Part I – Fundamental Principles. 1 The Basics. Voltage and Current. Resistance and Power.
It should have very high input resistance: If R1 is chosen to be much less than RL. First published: For the most accurate determination of ICQ. Butler
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As shown in Figure 1. In actuality. If A is a negative value. For jAj less than 1. Should x. For time-varying signals. RMS or power meters are not available dictating the measurement of peak amplitudes.
For instance. Lower case letters with upper case subscripts are used for AC signals with DC components. In many instances. Other common OpAmps include the OP If the output signal. In Figure 1. Figure 1. Lower case letters with lower case subscripts is used for AC signals.
Other manufacturers. MC is a good choice since it is the most commonly used and studied OpAmp available. LM by National Semiconductor. As will be shown in later sections of this text. For example. In order to discuss terminal characteristics of commercially available OpAmps. OP is used by Linear Technologies.
A ground reference is provided external to the chip package. Notice that the schematic symbol of the OpAmp does not have a ground pin. In many ways. Although commonly left disconnected by the circuit designer. OpAmp schematic representation. Unless used. VC C V Figure 1. All voltages are measured relative to a common reference node or ground which is external to the chip as is shown in Figure 1. In order to unify all discussions of OpAmp circuitry. Power is typically applied to an OpAmp in the form of two equalmagnitude supplies.
A short discussion of these rules of operation follows. Terminal voltages and currents.
Delay time considerations will be discussed at length in the third book of this series. In reality. A more realistic voltage transfer characteristic is shown in Figure 1. In this instance. Knowing the maximum value of the output voltage vo and the typical A. A transfer function is usually a mathematical description of the output as a function of the input.
If the output reaches the limiting values. In the OpAmp. For completeness. All OpAmps have low output resistance: Ideal OpAmps are considered to have zero-value output resistance. A virtual short implies that two terminals act in a voltage sense as if they were shorted.
Since the input currents are very small. Owing to the virtual short between the inverting and non-inverting terminals. Since the inverting terminal is directly connected to the output of the OpAmp. Although an understanding of the internal operation of the active device is desirable. By attaching external components to an OpAmp. It is a functional equivalent of the OpAmp which is not the actual circuitry in the OpAmp chip.
Equation 1. In the model. Since the output terminal of a voltage follower is connected to the negative input terminal of the OpAmp. It can easily be seen that large values of the OpAmp gain. To calculate the input resistance. Note that v t is applied directly to v2. When the resistance of the source is not zero.
Note also that all independent sources must be zeroed. Rin is. Example 1. Although the Transfer Function Analysis command is adequate for this particular example. Ro Ri 1. Solution 1: Solution 1 of Example 1.
SPICE solution using a test source at the output terminal of the equivalent model. Analysis of the OpAmp circuits in this chapter will rely on standard circuit analysis techniques. For most OpAmps. Since v2 is connected to the common or ground terminal.
A resistor Rf is connected to the output and provides a negative feedback path to the inverting input terminal. A discussion of these constraints is found in Section 1.
Rf may be prohibitively high. Rf must be very large to achieve large gain. Using Equation 1. Rf and RS. If RS is large. In some instances. Using KCL at node a. In this case.
Find the output voltage. For n input signals. Rf Xn vij: Since R1 D R2.! In time domain notation. Vi D Vi1 C Vi2: Note that the resulting output voltage requires the use of the phase of the two input signals. Rf vo D1C: Using the node voltage method of analysis. RA RC D: RB RD 1. By assuming an ideal OpAmp operating in the linear region.
In this example. What values of vb will result in operation in the linear region? Note that the node voltage at the output extends well above 15 V and below 15 V. As shown in the output plot.
An integrator is shown in Figure 1. Integrator circuit. Apply the node voltage method of analysis at node 1 assuming ideal OpAmp characteristics to yield.
But v1 D 0 due to the virtual ground so. A conversion between the two output expressions can be obtained by realizing that: A more typical result of analysis procedures is: AD RB 5: Typical resistor variation leads to the conclusion that the Equation 1. If the physical resistors used for RA and RC were exchanged. A good circuit designer would notice that the resistors in this example were paired in the worst possible manner. R2 and R R10 D R1. R1 D ADM D 1: R10 1.
With these restrictions. R1 R4 D R A fundamental understanding of these non-ideal properties allows the electronics designer to choose circuit topologies and parameter values so that the performance of real.
While the power supply. Here the OpAmp model is enclosed within the dashed box with an input voltage. Analysis of this circuit begins with replacing the OpAmp with its simple equivalent circuit as shown in Figure 1. A discussion of frequency dependent behavior and its close relative.
Good circuit design practices imply that near-ideal performance is the desired goal. With appropriate external element choices. For example: Ro Equations 1. In order to simplify the. Gf D Gl D In order to make the non-ideal performance mirror the ideal approximations. Rf if vo ii! RS is removed from the circuit. It yields a value for the input resistance of: If Rin is not to vary by more than a few ohms from the ideal value.
Rout D 0: Any non-ideal variations can be detected with a computer simulation: Input Bias Current. A reasonable set of restrictions on the external components has been shown to be: Ibias D Iin1 C Iin2: Variation in the load resistance will also alter the maximum output voltage swing: Power dissipation is package dependent with ceramic packages having the.
For protection purposes. Specialized OpAmps can operate with a one-sided supply: Metal and plastic packages have lower ratings with plastic the lowest.
Variations in the supply voltage. As has been mentioned before. While the list of non-ideal OpAmp properties may seem large. Many of common OpAmp applications can be described using only these characteristics and simple circuit analysis techniques. While the demonstrations have been kept to a minimum.
Typical values are in the — mW range. Additional OpAmp linear applications and many non-linear applications will be examined in later chapters. While a variety of linear applications have been examined in this chapter. A typical experimental circuit diagram for such a display is shown below: In general.
Later chapters will also investigate components used in the internal design of several OpAmp types and will shed light on non-ideal characteristics and the limitations these characteristics impose on OpAmp usage. In order to preserve this primary dependence on the external circuit elements.
Additional design restrictions concerning frequency response will be discussed in 9 Book 3. It should have very high input resistance: CMRR should be high.
When both indicated switches each is a pole of the actual switch are open. For a gain magnitude of ten in that path.
If a low-frequency function generator is used. After these topological design decisions. I D VAB: Safety regulations require that one terminal of the output of most function generators be at ground potential: For unity magnitude gain in the vB path.
Resistors with such small tolerances will ensure high CMRR. Both these resistor values are available as 0. Find the following: Peak-to-peak readings of the input and output voltages are found to be 1: Determine the current through the load resistor.
Draw appropriate circuit diagrams. Explain why this one statement can be used as a very simple model an OpAmp. Complete the design so that the output voltage is given by: What is the expression of the output voltage for the circuit shown for vi1 D cos.
In an attempt to create a non-inverting. For the circuit shown. Determine the. Assume ideal OpAmp characteristics. Compete the design of the circuit by determining R4 R1 so that io D vi mA: Ai D result.
A voltage. Find the output resistance. Design an OpAmp circuit to implement the following equation: ADM D Construct a graph of v2 vs. Let vo D vo. Hint at answer: Determine the output voltage. Assume that vo. Assuming that the OpAmp is ideal and the capacitor is uncharged. Show amplitude and time scales. For the circuit below. Given the attached circuit constructed with ideal OpAmps. In high-gain applications. What conditions must be met for the input resistance to be approximated by the ideal?
What conditions must be met for the output resistance to be approximated by the ideal? In the circuit shown. For the circuit shown in the above problem. Present theoretical validation of the results. Assume the OpAmp has the following properties: Av D Electronic Devices and Circuits: Discrete and Integrated.
New York. Analysis and Design of Analog Integrated Circuits.
Addison-Wesley Publishing Co. Digital and Analog Circuits and Systems. Rinehart and Winston. Analog Integrated Circuits. Electric Circuits McGraw-Hill Book Company While a device with such ideal characteristics may be impossible to manufacture.
Protection against misapplied currents or voltages. Vacuum tube devices have largely been superseded in electronic applications by semiconductor junction diodes. It is a simple two-terminal device whose name is derived from the vacuum tube technology device with similar characteristics: Its volt-ampere V-I transfer relationship is shown in Figure 2.
Reversing the polarity of the voltage and current still keeping the passive sign convention can yield. In two terminal devices. For many devices that are linear for example. Analytically the transfer relationship can be described as: In the second case the diode voltage violates the second model assumptions V D 1 violates the model assumption. Example 2. Semiconductor diodes are real diodes and have volt-ampere relationships that are in many ways similar to the V-I relationship for an ideal diode.
In the forward direction. While the studying the action of an ideal diode often provides useful insight into the operation of many electronic circuits. When in the conducting region the diode has a non-zero dynamic resistance. In the reverse direction.
When large reverse voltages are applied to a real diode in what should be the far extremes of non-conducting region the diode will enter a region of reverse conduction the Zener region due to one or more of several mechanisms. In the strongly reverse-biased region. For the diode the dynamic resistance is given by: When the diode is in its strongly forward biased region. Notice that the basic shape of this relationship is similar to that of the ideal diode with the following exceptions: It is important to note the temperature dependence of Equation 2.
While the temperature dependence of V t is evident, the temperature dependence of IS is not explicit. It can be shown through basic principles of semiconductor physics that IS is strongly temperature dependent. Other semiconductor materials exhibit similar variation of IS with temperature. A graphical demonstration of the change in the diode V-I characteristic with temperature is given in Figure 2.
Calculate the following: Notice also that the warm diode with 0. Heating leads to increased power dissipation which, in turn, leads to heating: Due to the non-linear nature of the V-I relationship for a semiconductor diode, analysis techniques for circuits containing diodes are complex. One of the simplest circuits involving a diode is shown in Figure 2. Equation 2. Structured searches can be easily performed using mathematical software packages such as Mathcad, Matlab or similar programs.
Find, at room temperature, the diode current, the voltage across the diode, and the power dissipated by the diode. Circuit Parameters V WD 5. Similar techniques applied to a hand-held calculator yield: A simple extension to Example 2. Assume the voltage source given in Figure 2.
In the development of this text, the authors used two of its derivatives: While numerical techniques are often quite useful to solve electronic circuit problems, they require the use of calculators or computers and in many circumstances provide no insight into the operation of the circuit. It is also necessary to know the parameters of the non-linear circuit elements with a reasonable degree of accuracy.
Diode V-I curves are often obtained through experimental procedures and only then are the parameters derived from the experimental data. A more direct approach to working with non-linear elements that has traditionally been taken is the use of graphical techniques. For circuits involving static DC sources the intersection set of values is called the quiescent point or Q-point of the circuit.
Figure 2. Load lines applied to time-varying sources. For the circuit shown, assume the following values: Find, at room temperature, the diode current as a function of time. On this plot the time dependent source voltage is also plotted as a function of time with the voltage axis corresponding to the diode voltage axis and the time axis parallel to the diode current axis. Notice the output waveform matches the simulation results of Example 2.
While each of these treatments has its place in the analysis of electronic circuits, it is often useful to. One such technique involves the regional linearization of circuit element V-I characteristics. When this technique is applied to a diode there are two basic regions. With real diodes the transition between the two regions lies at a positive diode voltage, hereafter called the threshold voltage, V.
Determine a linear forward-bias model for a diode with the following parameters: Care should be taken as to the polarity of the voltage source: While this technique gives an accurate approximation of the diode V-I characteristic about a Q-point, it is not always clear what Q-point should be chosen. In practice, one usually chooses a Q-point by: Approximate models create an error in the calculation of solutions.
Diode resistance. A reasonable guess at the dynamic resistance. Since curves for the diode threshold voltage as a function of diode current exist. Numerical solution of this problem as outlined in Example 2. Similar linear algebraic techniques give the solution: Simple linear algebraic techniques applied to two equations with two unknowns lead to a solution of: For this simple model choose the approximate value: Use of this model leads to inaccuracies much larger than seen in previous linear models.
It does. Calculate the diode current and voltage using: While method a allows for an exact dynamic resistance at some point. Each of these is based on the principle that the diode has a small leakage current that is fairly constant in the reverse bias region: Method b is easier to calculate. Linear reverse bias diode models. Numerical solutions of the type outlined in Example 2. Each solution yields diode voltage solutions that are extremely close.
In this particular problem. Clamping circuits are commonly used to detect information carried on pulse-width modulated signals i. Diode logic gates are simple circuits for performing Boolean operations.
Using the piece-wise linear model of the forward biased diode. Voltage multipliers perform an integer multiplication on the input signal to yield a higher output voltage. Diodes in a circuit can. Clamping circuits perform a level shifting operation on the input waveform.
In particular. Examples of clipping circuits are shown in Figure 2. Diode clipping circuits. Table 2. Rs rd vi C. Solution 3: Output waveform for Example 2. Solution 2: Transfer Function Analysis A solution can be constructed from a transfer function analysis of the circuit as shown below. RS parasitic resistance.
If vi is a sinusoidal voltage with peak voltage Vm and radian frequency! Transfer function solution to Example 2. Substituting Equation 2. If Vm is very small. T 2 But! In real systems. Vm sin! Pac 2. Transformers also provide isolation of the circuit from the household power line. What is the peak output voltage? Apply Equation 2. SPICE circuit topology. Many of the SPICE model parameters are useful for frequency analysis that is used in the latter chapters.
Observe that in the original circuit Figure 2. A large isolation resistor at the secondary facilitates the reference to ground at the secondary. If the breakdown voltage is exceeded. If ground isolation is not required. Note that the secondary winding is capable of providing twice the voltage drop across the load resistor.
In the negative half cycle of the voltage across the secondary of the transformer. In both half cycles. From Equation 2. What is the output DC voltage? Since the transformer turns ratio is In Figure 2. A clamping circuit is shown in Figure 2.
Peak detector and associated waveforms. Clamping circuit. If the diode is reversed. With a peak input signal Vm. Across diode D1. Input and output wave forms for the clamping circuit.
Diode voltage doubler circuit. Output signal from a voltage doubler circuit. For positive vi. In the OR gate. OFF IZ. A wide range of Zener diodes are commercially available over a wide range of breakdown voltages and power ratings to W. Zener breakdown occurs in the heavily doped p. Regardless of the mechanism for breakdown. To obtain a steeper reverse breakdown characteristic. For avalanche breakdown. Since the reverse current increases rapidly with small changes in the diode voltage drop.
If IBV is large. R2 If the breakdown voltage VZ is less than vO. Zener diode voltage reference circuit. If the breakdown voltage VZ is greater than vo. Replace the Zener diode in the circuit. To simplify the analysis. IL the range of RL is found to be 3: R must be the intersection of the limits determined by the above equation: I Since regulation must occur for both extremes of the source voltage. RL D VZ. Vs 50 R Since regulation must hold for all values of R. If R1 is chosen to be much less than RL.
If the Zener diode is to carry large currents over much of the operating cycle. Although the Zener diode is small in size and requires substantially less circuit volume than large capacitors. At the peak current IP corresponding to the voltage VP. Although the conventional p-n junction diode and the Zener diode are the most common diode types used in electronic design.
Varactor Diode. Esaki who announced the new diode in voltage-current characteristic is shown in Figure 2. Voltage-current characteristic of a tunnel diode.
For small forward voltages in the order of 50 mV in Ge. Schottky barrier diode. At the valley voltage. As the voltage increases beyond VP. Some load lines may intersect the tunnel diode characteristic curve in three places: At the peak forward voltage. High frequency microwave oscillators are often designed so that the tunnel diode is biased in its negative dynamic resistance region.
Tunnel diode symbol. Metal-semiconductor diode voltage-current characteristics are very similar to conventional p-n junction diodes and can be described by the diode equation with the exception that the threshold voltage V is in the range from 0.
Metal-semiconductor diodes are formed by bonding a metal usually aluminum or platinum to n. Beyond VV. Schottky diodes are often used in integrated circuits for high speed switching applications. In the Schottky diode. Intensifying the light on the photodiode induces hole-electron pairs that increase the magnitude of the diode reverse saturation current.
Schottky diode symbol. If the intensity of the light on the photodiode is constant. In order to make this energy conversion.
Photodiode symbol. Since the photocurrent can be very small. By appropriate doping. Characteristic curves of a photodiode. When using the LED in a circuit. When the LED is conducting. LED symbol. P5 is the optical power falling on the photodetector. Diode applications utilize the characteristic properties of the diode in one or more of these three regions of operation: Large reverse voltages force the diode into breakdown and the dynamic resistance again becomes small. Simple LED driving circuit.
While nearly-exact. Schottky diode. One such electronic application operates with the following power requirements: Summary Design Example Many electronic applications have a need for backup electrical power when there is a primary power failure. In later chapters.
During normal operation the system state is: All design goals can be met with a network composed of diodes and a resistor. Design a backup power system that will provide adequate auxiliary power when the primary power source fails i. VCC D 0. Battery capacity is measured in the product of current and time i. Capacitive backup is a poor choice for this system: D1 blocks current discharge to the primary power source and D2 provides a low-impedance path to the load.
During backup operation the system state is: Auxiliary power voltage must be greater than the minimum voltage required by the load plus V and smaller than the minimum voltage provided by the primary power source minus V: A 6 V battery is a good choice for this system. Of the three given choices. Proposed backup power system. Depending on the type of battery chosen. In each case the diode must be capable of carrying a minimum of mA continuously.
Maximum recharging current determines the capacity of the Zener diode. Battery recharging current must be limited. Every battery type has a recommended rate of charge in order to maintain proper operation for a long life. As batteries are overcharged. A typical overvoltage for small batteries is approximately 0.
For the diode in the above problem. A Silicon diode has a reverse saturation current of 1 nA and an empirical scaling constant. A Silicon diode has a reverse saturation current of 0. Assume operation at room temperature. A diode is operating in a circuit in series with a constant current source of value I. What values of the reverse saturation current and empirical scaling constant allow this diode to be modeled by the diode equation? At room temperature.
If ID varies over the range 4: Find ID if the diode is operating in the forward-bias region. A diode at room temperature has 0. When a 20 A current is initially applied to a Silicon diode K of a particular characteristic.
Determine the current I in the given circuit if the diode is described by: Find the values of all currents. Assume that the diodes are ideal. Find the values of I and V for the circuits shown below. Find the diode current in the given circuit as a function of time. A Silicon diode has a reverse saturation current of 8 nA and an empirical scaling constant.
Let vi. How much current is drawn away by the load? Also indicate all slopes and voltage levels on the sketch. Assume Silicon diodes. In each region indicate which diode s are ON. For the circuits below.
Assume diodes with the following properties: Use transformer coupling. Piece-wise linear models of diodes may be used for your analytical design. Given the following diode circuit. Piece-wise linear models of diodes may be used for your design. Assume no losses by the transformer and a diode V D 0: Provide only the analytical solution. Design a half-wave unregulated power supply to provide an output DC voltage of 10 V with a peak-to-peak ripple voltage of 0.
Assume a V. In each region indicate the state of each diode. Assume vi. Analyze the voltage tripler-quadrupler shown. Given the following circuit and diode data: Plot the output when the input signal is vi. Design a circuit that clamps a signal to 5 V and clips it below 5 V. It is receiving power from an unregulated power supply that can vary between 7. A simple Zener diode Supply voltage Zener voltage Zener current range voltage regulator is under design.
A load draws between mA and mA at 5 V. Be sure to specify the power rating of any necessary resistors. Design a wall socket power converter that plugs into a standard electrical wall socket and provides an unregulated DC voltage of 6 V to a portable Compact Disk player. Assume no losses by the transformer and diode V D 0: Show the circuit diagram for the completed design. Is a redesign necessary? What is the maximum load current. Design a Zener diode voltage regulator using a 5 V Zener diode that regulates for diode currents between 50 mA and 1.
For the circuit shown below: Adjust the circuit parameters to insure stable 6 V output from the converter. Each diode is the given circuit is described by a linearized volt-ampere characteristic with dynamic forward resistance.
H and Mitchell. Redwood City. Introduction to Electronics. Electronic Circuit Analysis: Basic Principles Electronic Design: Circuit and Systems.
McGraw-Hill Book Company.. Second Edition. Diode curve for Problems 2. Diode curve for Problem 2. Semiconductor Micro-devices and Materials.. Electronic Materials Science: New York.. Materials and Devices for Electrical Engineers and Physicists. Microelectronic Circuits. Solid State Electronic Devices. It can be found. Before proceeding with technical descriptions of the operation of a BJT.
BJTs are constructed with two p-n junctions sharing a common region. BJT circuit symbols.
Book 3 will explore the higher frequency ranges. Because there are. In order to simplify the analysis of BJT operation. IB is the current entering the base of the transistor as is drawn in Figure 3. In order to use the BJT as a linear device.
As is true of all chapters in this book. Figure 3. A set of empirical curves for a typical npn BJT is shown in Figure 3. Input characteristics: Ebers and J. Output characteristics: Common base characteristics Figure 3. December One of the most accurate and simple theoretical characterizations of the BJT are the EbersMoll equations.